Fun with T-amps - I didn't know what I was missing.

[fastbike1]

Re: Fun with T-amps - I didn't know what I was missing.

Bear in mind that "chipamps", "T-amps", and class D amps are all a little bit different in that the amplification is accomplished by distinctly different ICs.

For JohnnyRichards: here's a really tempting amp newbie project that's getting a lot of buzz. US built.

http://classdaudio.com/index.php/cla...nsformer.html;)

[cowtown]

Re: Fun with T-amps - I didn't know what I was missing.

Cowtown, I know it's a little OT, but those grills are really cool.

Hi John,
I put a few more pictures of the grills in post #6. Hopefully they show the design a little better.

1) What's tackboard (is it cork, or is it stronger)? Sandwiched? Are you gluing layers together for thickness and strength?

It's some sort of manufactured hardwood with a shiny machined finish on one side. It's only 1/8" thick but very easy to route and sand. It's similar to the pegboard with all the holes in it that you hang tools from. Maybe someone here knows a better name for it?

Anyway, each grill consists of two identical routed circles of tackboard, and one of the two then has the magnet holes punched in.

On the circle without the magnet holes, I stretched the speaker grill cloth across the middle, around to the back side, and glued it on the back side. Then I "sandwiched" the other circle onto the back of the one with the cloth installed. The purpose of the second circle is to carry the magnets and hide the glued part of the cloth. When everything is painted black, you really have to get up close to see that there is more than one piece making up the grill.

2) How do you cut such nice circular shapes (the overall shape of the grill frame...I assume the small holes are done with a punch)?

I used a Jasper jig with a sharp new spiral upcut bit for the circles, then a punch for the magnet holes.

3) Statement Monitors in your garage?!?!?!??!

It's a protective measure (for the speakers) - I drag them into my living room regularly, but with a crawling infant, a three year old, and a six year old, these Statements need to hide most of the time. That's also why I put the grills on them, even though I love looking at the cool drivers.... :D

[johnnyrichards]

Re: Fun with T-amps - I didn't know what I was missing.

Bear in mind that "chipamps", "T-amps", and class D amps are all a little bit different in that the amplification is accomplished by distinctly different ICs.

For JohnnyRichards: here's a really tempting amp newbie project that's getting a lot of buzz. US built.

http://classdaudio.com/index.php/cla...nsformer.html;)

I have seen those around, look nice The link is 404 though.

Love the sig, Dylan is the man.

[critofur]

Re: Fun with T-amps - I didn't know what I was missing.

Now that you see how fun chip amps are, I suggest that you revisit the LM3886 "gainclone"...

It seems to me that in general the opinions I've read from people that have used both prefer the sound of these T-amps over the LM3886 based amps?

[cowtown]

Re: Fun with T-amps - I didn't know what I was missing.

It seems to me that in general the opinions I've read from people that have used both prefer the sound of these T-amps over the LM3886 based amps?

I'd be interested in hearing more about this. I have also read a bunch of T-amp/class D vs. GainClone discussions and there doesn't seem to be any clear winner that I can see. The owners of each defend them equally.

To me, the question is really how good is "good enough" in my environment, with my speakers, and my hearing. I'm really not sure I'd notice a difference, but would like to find out.

[Pete Schumacher]

Re: Fun with T-amps - I didn't know what I was missing.

It's some sort of manufactured hardwood with a shiny machined finish on one side. It's only 1/8" thick but very easy to route and sand. It's similar to the pegboard with all the holes in it that you hang tools from. Maybe someone here knows a better name for it?

Masonite or HDF

D, Rose used in the construction of the Byzantiums

[scid714]

Re: Fun with T-amps - I didn't know what I was missing.

How friendly are they for a "newbie" to DIY amps?

very friendly plus well documented.There is a sticky on diyaudio.com for the power supply that is very informative plus endless discussion on the amps themselves. I'm building a D/C servo LM3886 board at the moment for my OS mtm's. give them a try super easy if you can build a crossover you won't have any problem's

[jclin4]

Re: Fun with T-amps - I didn't know what I was missing.

Also lots of info at Decibel Dungeon. Here's the gainclone FAQ:

http://www.decdun.me.uk/gaincloneFAQ.html

[AJ]

Re: Fun with T-amps - I didn't know what I was missing.

More chipamp links...

http://sound.westhost.com/project19.htm

http://sound.westhost.com/project72.htm

http://sound.westhost.com/project115.htm

http://sound.westhost.com/project127.htm

[DDF]

Re: Fun with T-amps - I didn't know what I was missing.

Also lots of info at Decibel Dungeon. Here's the gainclone FAQ:

http://www.decdun.me.uk/gaincloneFAQ.html

The article points out that the speakers should be high sensitivity with the gain clones. Thats not really true: the speakers used should not have low impedance anywhere.

You can get 60 watts out of a gain clone (which is more than useable even with 85 db sens speakers), but if it dips below 4 ohms, they go into protect mode with all the resulting sonic nasties that entails.

[fastbike1]

Re: Fun with T-amps - I didn't know what I was missing.

Sorry, don't know why it went 404. The link was to the CDA-254L kit. Big power supply, transformer, amp. The amp is 125w/c in 8 ohms, 250X2 into 4 and can be bridged to 500w. $210 for the kit.

Some of the LM4780 gainclones can be built in modes that handle 4 ohm speakers. Check audiosector.com

I have seen those around, look nice The link is 404 though.

Love the sig, Dylan is the man.

[AJ]

Re: Fun with T-amps - I didn't know what I was missing.

The article points out that the speakers should be high sensitivity with the gain clones. Thats not really true: the speakers used should not have low impedance anywhere.

You can get 60 watts out of a gain clone (which is more than useable even with 85 db sens speakers), but if it dips below 4 ohms, they go into protect mode with all the resulting sonic nasties that entails.

They can drive reactive 4ohm loads with adequate heatsinking. Chipamp or not, a LM3886 is still capable of 60W/4R so just bolting it to an aluminum panel is no where near adequate, and will lead to the protection circuits kicking in. Also, the power supply rail voltage should be considered. Lower load impedances dictate a lower supply voltage. When operated within their limits they work fine with 4ohm speakers.

As for Tamp vs. chipamp, everything depends on implementation. If the person, for instance, built a typical gainclone (no real heatsinking, over +/-30V rails, etc...) and operated a LM1875, LM3875, LM3886, etc... past it's current or temp limits I could see how a Tamp operating within it's limits would sound better. Otherwise, I would expect no difference in sound between the two, if they were both designed and built correctly.

[philiparcario]

Re: Fun with T-amps - I didn't know what I was missing.

I have heard good t-amps red wine audio had some nice ones. I have not got hold of a hi power t-amp. 45 watts per channel.


But I have had gainclones at 38watts 8ohm and 68watts 4ohm. if they were built well they sound very nice. I like lower voltage for my gainclones. 24ac upped to 33 or 35 dc work very well. Also lets this 50 volt caps be used saves some money. here is the pdf.

http://www.national.com/ds/LM/LM3886.pdf

[robertf]

Re: Fun with T-amps - I didn't know what I was missing.

I built a classdaudio amp kit paired with an old Arcam Alpha 9 integrated amp used as a pre amp only to drive my Mini-Statements. The Amp sounds great. This is the best setup that I have had so far. I believe it finally pushes me out of Mid-Fi status and into the beginnings of the Hi-Fi realm.
Here is link for my amp thread http://techtalk.parts-express.com/sh...d.php?t=217086
Also large thread here http://www.audiocircle.com/index.php?topic=76400.0

I listened to Sheffield Labs “Drive” last night and it sounded fantastic. Still have a damn fool grin on my face:D

Robert

[johnnyrichards]

Re: Fun with T-amps - I didn't know what I was missing.

You guys have convinced me that DIY might be the way to go for amps. Can I compete with the five channel Emotiva price/performance? That was going to be my next amplifier purchase.